8 MINI-CIM SWERVE

[asid61]

Originally Posted by EricH

This is, after all, the sort of thing used to power machine shops in the way olden times: one power source, every tool has a belt off of that source and a clutch to disengage itself...

"In olden times" being the key word. I saw a thread on Practical Machinist a couple days ago showing a shop from the 1850's being powered up today, with the spindle running overhead.

I think it would be possible to do the shunting power method you suggest. And it would be super cool. But it would be easier to use 3 gearboxes; 2 for drive (6 cim + 4 minicim) and 1 for endgame and manipulators (4x RS-775 18v).

[jman4747]

Originally Posted by Max Boord

Good point. Although something tells me figuring out the exact tripping curve of a given main breaker at a given temperature would make a closed loop system very complex. Also, if your are limiting power on your 6 cim+ 2 mini cim drive why wouldn't you go with a simple 6 cim (and software limiters)? With 6 cims only providing a 20-30% acceleration boost over 4 cims, i can't really see how adding mini cims would be much of a gain in top speed or acceleration, not to mention the added complexity of custom or additional COTS gearboxes.

This.

I don't see how anyone could ever get an advantage from actually using near all allowable motors even now, and I don't think the OP is saying that's the sort of design this encourages. Allowing more motors in this context is to allow more options. Sure you could build two 3 cim 4 mini-cim gearboxes for each side of a tank drive but you're not going to get to use all 3782 watts. Extremes aside... in reality reducing motor restrictions wouldn't change much as the physical and hardware constraints make using all allowed power imposable. As stated before the context is more options and maybe it's doesn't need to be exactly this but I think FRC could use some more variety.

[Lil' Lavery]

Originally Posted by RyanShoff

http://gallery.marswars.org/2014-bui...G_3784.JPG.php

Our swerve was originally setup for 1 cim and 1 mini-cim per module. Ultimately we ended up cutting off the extra spot. Mostly because we wanted to use slip rings and not worry about ripping up wires.

Wouldn't these modules exit the frame perimeter at various points in their rotation?

[JesseK]

Originally Posted by jman4747

This.

I don't see how anyone could ever get an advantage from actually using near all allowable motors even now,

Just because the advantage looks relatively small does not mean it doesn't have major impacts on gameplay. Do a few comparisons of speed vs distance while accelerating and it easy to see that 'mere' 20-30% quickly converts into much higher energy impacts since the energy imparted is proportional to the square of the velocity. These will inevitably occur more often during gamely since they don't require much room for the acceleration.

The advantage then becomes "find the robot who can't do much on offense and which has 6cims, then tell them to go push the other robots around. If they hit the opponents enough, maybe the opponents will just stop working and then we can win".

[Oblarg]

Originally Posted by JesseK

Just because the advantage looks relatively small does not mean it doesn't have major impacts on gameplay. Do a few comparisons of speed vs distance while accelerating and it easy to see that 'mere' 20-30% quickly converts into much higher energy impacts since the energy imparted is proportional to the square of the velocity. These will inevitably occur more often during gamely since they don't require much room for the acceleration.

The advantage then becomes "find the robot who can't do much on offense and which has 6cims, then tell them to go push the other robots around. If they hit the opponents enough, maybe the opponents will just stop working and then we can win".

Or, in more legitimate terms, if you hit them enough they will find it hard to position themselves to accomplish game tasks.

I think it is unfair to characterize tough defense as "hitting people with the hopes their robot breaks." We played defense a lot this past year, and our goal in robot-robot contact was never to cause damage. Good defense is about being in the right place at the right time and knowing how to interact with the robot you're trying to defend against, not simply hitting them as hard as possible. Having additional motors definitely helps with this, both by allowing you to push for longer when needed without tripping a breaker (especially if your opponent cannot do the same), and by allowing you to get to where you need to be faster (and, as a lot of defense is stop-and-go and rapidly-changing, acceleration is critically important for this).

[Nick Lawrence]

Originally Posted by Kevin Ainsworth

Would any one else like to see (8) MINI-CIM motors allowed so the swerves can be on par with the (6) CIM tank drives?

Looks like an 8 MINI-CIM motor swerve drive would be very close to power and weight of 6 CIM motor 6WD/8WD.

POWER
CIM 6 x 337 watts = 2022 watts total power
MINI-CIM 8 x 230 watts = 1840 watts total power
Within 10% instead of down 50%.

WEIGHT
CIM 6 x 2.80 lbs = 16.8 lbs
MINI-CIM 8 x 2.16 lbs = 17.28 lbs

Seems like the current rules favor a 6 CIM tank over a 4 CIM swerve for acceleration and top speed. I personally would like to see this somehow corrected. Maybe separating BAG motors from the MINI-CIM motors and a allowing 8 MINI-CIM motors?

This could be calculated by adding the watts of all motors used with a not to exceed. Or even more simply a CIM=1 and a MINI-CIM=.66 or .75 and a maximum of 6 when added up.

What's your thoughts?

While I'm all for having as many motors as we can get, I'm not sure I agree with your specific reasoning here. You're asking for more Mini-CIMs based on your team's specific swerve module design. While your swerve was absolutely beautiful and effective, there are ways to have the same power as a 6 CIM traditional 6WD via a coaxial setup. I don't feel that you are at a disadvantage by the rules at all by having a swerve - it was your choice, and the same amount of power is available to you. That being said, I would have to agree with Brendan about having difficulty of putting that power to the ground, even with 8 Mini-CIMS with two per module.

Personally, I would love to see the rules opened up to allow teams to use any number of a few models of motors, and it is up to them to design around tradeoffs of weight and battery consumption. I would never want to see an open field again if we had these rules, however. This year was violent enough.

-Nick

[JesseK]

Originally Posted by Oblarg

Or, in more legitimate terms, if you hit them enough they will find it hard to position themselves to accomplish game tasks.

I think it is unfair to characterize tough defense as "hitting people with the hopes their robot breaks." We played defense a lot this past year, and our goal in robot-robot contact was never to cause damage. Good defense is about being in the right place at the right time and knowing how to interact with the robot you're trying to defend against, not simply hitting them as hard as possible. Having additional motors definitely helps with this, both by allowing you to push for longer when needed without tripping a breaker (especially if your opponent cannot do the same), and by allowing you to get to where you need to be faster (and, as a lot of defense is stop-and-go and rapidly-changing, acceleration is critically important for this).

What I really find striking is that you seem to being saying the point of defense is to hit and that the hits have no "legitimate" post-match impacts to the teams on the receiving end. You also follow that up with saying that more motors allows a team to hit harder, more often and for longer, all in the name of gaining position.

The reality of the season (particularly when examining 4464's video) is that the defender simply wants to use the acceleration to make up for the fact that it screwed up and was already out of position. This was evident even when examining other events' video (which I did a ton of while scouting for Champs) and correlating the teams who won via defense with teams who had 6 CIMs at champs.

The point of this thread, and the counter argument I'm making, is discussing whether or not increasing available power to the drive trains makes sense from a game design perspective. I don't know that you've argued in favor for either so much as you've tried to justify and/or glorify what 6 CIMs can do. Perhaps you could clarify for me?

[Oblarg]

Originally Posted by JesseK

What I really find striking is that you seem to being saying the point of defense is to hit and that the hits have no "legitimate" post-match impacts to the teams on the receiving end. You also follow that up with saying that more motors allows a team to hit harder, more often and for longer, all in the name of gaining position.

The point of defense is to prevent the opposing robot from completing the scoring task. The easiest legal way to do this is by hindering their movement. Hitting them does just that. There's a reason we have bumpers and the manual every year stresses that robots must be robust.

We did not incur a single penalty this year for overly-rough contact. I take that as pretty firm evidence that we were not causing undue damage to other robots out there. I'm sure we contributed a fair bit to other team's wear-and-tear (after DC we found a nice big dent on our AM14U), and I've made no claim that this isn't a "legitimate" effect, but if FIRST did not want this to happen the rules would not explicitly provide for bumper-to-bumper contact between robots.

The reality of the season (particularly when examining 4464's video) is that the defender simply wants to use the acceleration to make up for the fact that it screwed up and was already out of position. This was evident even when examining other events' video (which I did a ton of while scouting for Champs) and correlating the teams who won via defense with teams who had 6 CIMs at champs.

This argument seems to be along the line of "if you had perfect drivers, the extra acceleration would not be necessary/helpful." Which might be true (I reserve judgement, though I find it dubious), but it's completely irrelevant, because no one has perfect drivers and no one is in the exact right place at every moment.

The point of this thread, and the counter argument I'm making, is discussing whether or not increasing available power to the drive trains makes sense from a game design perspective. I don't know that you've argued in favor for either so much as you've tried to justify and/or glorify what 6 CIMs can do. Perhaps you could clarify for me?

I've made several very specific points as to why 6-CIM drives can be an advantage for certain strategies. In fact, in this response you've pretty much acknowledged one of them (giving your drivers more headroom to make up for mistakes). Moreover, I don't really understand your second-to-last sentence here - what would an argument in favor of 6 CIM drives as a design choice consist of if not "justifying what they can do" for a robot?

You seem to be making a blanket statement that "any team that claims success due to additional motors on their drive is either downplaying the negatives or was trying to damage other robots." I contend that this is clearly false.

Now, there is a discussion to be had about whether or not FRC, as a whole, is better for the move towards bigger and beefier drive-trains, but that is a separate question entirely.

[JesseK]

Originally Posted by Oblarg

You seem to be making a blanket statement that "any team that claims success due to additional motors on their drive is either downplaying the negatives or was trying to damage other robots."

The statement is more like "Any team that claims success due to additional motors on their drive has accounted for the negatives in a single subsystem of their own overall robot and was oblivious to or completely ignored the damage they did to other robots multitudes of subsystems".

The rules allow this. It doesn't meant the rules should allow this. I don't fault 4464 for its defense this year since it was actually pretty clean relative to other matches I've watched.
- You capitalized on it - great, I'm glad your team got to move on
- at the expense of other teams - not so great
- whom you never acknowledged or offered to help afterwards - and here's the point of reducing the allowed power on the drive train. Most defenders didn't care ("undue damage"? Really, we deserved damage?)

To phrase it differently...

There's a very public story from 2007 about one team's entire mechanism, made out of 1/8" tube and securely attached, being ripped out by a defender with a powerful drive train (for that year) after the defender shoved the offensive robot into the Rack. The comment from a ref supposedly was "well the mechanism should have been made stronger". The very well-worded public counter argument was something like "to account for THAT type of defense, it is impossible to make a robust enough mechanism".

The story still applies 7 seasons later. There is no type of "robust", without going to extremes, that can be used to account for the amount of power available to drive trains these days and how teams are choosing to use it.

[Oblarg]

Originally Posted by JesseK

The statement is more like "Any team that claims success due to additional motors on their drive has accounted for the negatives in a single subsystem of their own overall robot and was oblivious to or completely ignored the damage they did to other robots multitudes of subsystems".

I still think this is overly-strong and not at all necessarily true.

The rules allow this. It doesn't meant the rules should allow this. I don't fault 4464 for its defense this year since it was actually pretty clean relative to other matches I've watched.
- You capitalized on it - great, I'm glad your team got to move on
- at the expense of other teams - not so great
- whom you never acknowledged or offered to help afterwards - and here's the point of reducing the allowed power on the drive train. Most defenders didn't care ("undue damage"? Really, we deserved damage?)

I don't see that our success this year was "at the expense of other teams." Granted, I don't have perfect knowledge or perfect memory, but I try to keep track of how the matches go so I can offer help to teams if their robots are damaged, and I can't think of any matches where our defense caused a lasting problem to another robot that cost them future success, and I certainly would not have advocated for a defensive strategy if I felt that this was an unavoidable consequence of it.

Moreover, "deserved" is a loaded term - rather, there is a certain level of damage that your robot will attain during normal competition that is deemed acceptable under the rules. This has to be the case if robot to robot contact is going to be permitted at all. Designing for and dealing with this is as much a part of the game as building mechanisms to manipulate the game pieces and score points. I do not think our strategy last year went past this standard in terms of impact on other robots.

To phrase it differently...

There's a very public story from 2007 about one team's entire mechanism, made out of 1/8" tube and securely attached, being ripped out by a defender with a powerful drive train (for that year) after the defender shoved the offensive robot into the Rack. The comment from a ref supposedly was "well the mechanism should have been made stronger". The very well-worded public counter argument was something like "to account for THAT type of defense, it is impossible to make a robust enough mechanism".

The story still applies 7 seasons later. There is no type of "robust", without going to extremes, that can be used to account for the amount of power available to drive trains these days and how teams are choosing to use it.

I don't think you can construe the benefit we gained from a 6CIM drive drain as being in this category. We did not benefit because we caused irreparable damage to sturdily-built mechanisms; indeed, I can't think of a time we caused serious damage to any other robot's mechanism.

And, again, whether 6-CIM drives are a good thing for FRC in general is a completely different question from how beneficial they are in robot design.

[BBray_T1296]

Originally Posted by Lil' Lavery

Wouldn't these modules exit the frame perimeter at various points in their rotation?

Looks like yes, but why couldn't they?

[cgmv123]

Originally Posted by Lil' Lavery

Wouldn't these modules exit the frame perimeter at various points in their rotation?

As long as they start inside the frame perimeter, those modules leaving the frame perimeter is legal under the 2014 rules, which didn't have a limit on appendages, just an extension limit (which the modules would not exceed.)

[nuclearnerd]

Originally Posted by JesseK

The point of this thread, and the counter argument I'm making, is discussing whether or not increasing available power to the drive trains makes sense from a game design perspective. I don't know that you've argued in favor for either so much as you've tried to justify and/or glorify what 6 CIMs can do. Perhaps you could clarify for me?

Actually, the point of this thread was simply whether to allow 8 mini-Cims. The argument "not to increase available power" has nothing to say on this question, given that 8 mini-cims have a smaller TPE than 6 Cims, which are allowed.

[Tyler2517]

Question on swerves in general.
If you had a 4 module swerve with 1 cim per wheel in the front.
Then 2 cims per wheel in the back. Could you use pid loops to make it work?

[Aren Siekmeier]

Originally Posted by Tyler2517

Question on swerves in general.
If you had a 4 module swerve with 1 cim per wheel in the front.
Then 2 cims per wheel in the back. Could you use pid loops to make it work?

Sure, if tuned properly. But the wheels with 2 CIMs will always be waiting for the wheels with 1 CIM to accelerate (for example if the 2s are on the left and the 1s are on the right), so you don't increase your top acceleration like you do with the motors evenly distributed.